From bee3f5615a733beb4f3175f61ed65fd338484f67 Mon Sep 17 00:00:00 2001
From: Last Davis Vern <davis.last@psi.ch>
Date: Tue, 12 Aug 2025 11:33:01 +0200
Subject: [PATCH] Figured out the answer to a question posed by one of my
 comments in the past

---
 frappy_psi/tnmr/sequence_fileformat.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/frappy_psi/tnmr/sequence_fileformat.py b/frappy_psi/tnmr/sequence_fileformat.py
index ce0005ea..51af2ff9 100644
--- a/frappy_psi/tnmr/sequence_fileformat.py
+++ b/frappy_psi/tnmr/sequence_fileformat.py
@@ -236,7 +236,12 @@ def get_event_header(event_type, vals, tables, table_reg, tuning_number, col_del
             
             dwell_us = acq_time / acq_points
             dwell = f'{dwell_us*1000}n'
-            freq = 1/(dwell_us/1e6) / 2 # put it in Hz. TODO: Figure out why the factor of 2 is necessary...
+            
+            # spectral width (here "sweep") and dwell time are linked by the relation
+            # DT = (2*SW)^(-1)
+            # Therefore, SW = 1/(DT*2)
+            
+            freq = 1/(dwell_us/1e6) / 2 # put it in Hz.
             sweep = f'{freq}Hz'
             filtr = f'{freq}Hz'